Hello AllI am currently evaluating if I should upgrade my EOS 550D with a really nice 6D. The main reasons for this are: - bigger body, but still not as big as the 550D with the battery kit mounted, thus it's better in hand- bigger viewfinder- MUCH better low light performance (probably the main reason)- full frame sensor (a little bit more detail)The main use of the camera is everyday pictures. I always carry my 550D with a Sigma 18-125 lens with me around and I like the range of this lens. I picture mostly animals, landscapes and buildings, but normally no people. I compared the two lenses over at Dxomark, here the compare with the 5D MK2: http://www.dxomark.com/index.php/Lenses/Compare-Camera-Lenses/Compare-lenses/(lens1)/211/(brand)/Tamron/(camera1)/483/(lens2)/164/(brand2)/Canon/(camera2)/483The canon is a bit sharper, but with "only" 1/3 of reach. I don't think I'll feel the difference of 24mm to 28mm at all with my shooting habits.What do you think, should I take the better and sharper Canon lens, but loose quite a bit reach, or is the difference in sharpness anyway not visible if I'm not going to pixel peep?ThanksPatrick

+1 for the 24-105, and figuring out what sort of focal lengths you commonly use before making a decision.

If all you want to do is replicate your ~125mm on crop with FF, just crop the 6D images down to what portion of the frame your 550D sees - the 105mm of the 24-105 will then be almost there. And if you start to pixel peep and find its not for you, later on get the 70-200 f4 (IS or non IS), or the equally excellent 70-300L.

Usually its recommended to invest more in your lenses than on bodies. A quality lens should last for ages, whereas a body dates much quicker.

While these L options cost a lot more money, it all depends on whether you really want to get more out of your photography by spending on equipment. That Tamron is dirt cheap...

If you're not going to pixel peep, why even buy a 6D at all? You're talking about going from an older Rebel to full frame, yet you're worried about sharpness, but you're not going to pixel peep? Doesn't really make sense to me. Spending that much money and not being serious enough about the files you produce, doesn't make sense. To each their own, though. You really don't need a $2k body if you don't pixel peep.

I disagree with RS. To duplicate the reach of a Sigma 18-125 lens on your 550D, you would need a 28-200 lens for a 6D. So that would be a center crop resolution equal to about 180mm on the 6D. If you take a lot of pictures of animals, the 24-105 on a 6D, will not be enough of a telephoto. 105mm on a 6D, is like a 60mm lens on your 550D. Do you shoot many animals at 60mm? If you do, and you rarely go above that, then by all means, the 24-105 will suit you.

This is a problem for people getting into full frame. You assume you can have a compact lens for walking around like you did on the smaller camera, that will give enough reach for wildlife or animals...but it just isn't going to happen. Basically, you will have to give up the wide end, and get a 70-200...I suggest an f/4, without IS. $600...cheaper than the 24-105, and as sharp if not sharper. I've rented the 24-105, and have owned the 70-200 for 3 years. You could also just buy both lenses.

If you're interested in taking good pictures of animals, especially anything that moves relatively fast, you might as well spring for a 5D3. The 6D is best suited for slower action, and for portraits.

Thanks for the replies so far. Most my pictures are shot with the 18-120 range, so I can't really say if I would shoot more with a longer lens.The two kits cost both more or less the same (around 2850 USD inc. Taxes - 2650 CHF), so the price here is not an issue.I know the L lenses are great, I own a great Canon 100 mm 2,8 IS USM I also own an old Sigma 400 mm AF Macro HSM and an even old (and fairly lousy) Canon 75-300 mm without IS. Then also a Canon EF 50mm F1.8 II which is fine for portrait. Oh, the only thing that I will really miss on the 6D is the not integrated flash For most of my pictures was the integrated enough.

Here's my cat shot with a 1D Mark IV and 24-105, zoomed in at 105mm. Of course on a 6D, this is equal to 135mm field of view...and on your 550D this is like 73mm. Notice only his back and tail are in focus, the servo autofocus could not keep up with him coming at me with this lens. I'm not sure many lenses could. Granted this was minutes after I first received the 1D4, and I never quite became an expert at setting its AF. The 24-105, is not known for having a fast autofocus. It's a fine lens though, I certainly plan to get one when I decide on which full frame camera to buy. This one did have quite noticeable CA toward the periphery at the wide end, but it was still sharp everywhere. It was actually a bit less sharp zoomed in to 105mm, than at the wide end.

Stay aware from the Tamron 28-300mm VC lens if you are worried about sharpness. I have Canon's 28-300L IS lens and love the overall quality and versatility that it provides but it is quite large and heavy to lug around all day. I picked up a copy of the Tamron thinking that it would be "good enough" for when I wanted to travel light (about 1/3 the weight and price compared to the Canon). The image quality is fine for smaller prints but is too soft for large prints (IMO). The VC works great but the lens is a slooooooow lens. Even though it is an f3.5-6.3 (the Canon is 3.5-5.6) it transitions from 3.5 down to f5, 5.6, and 6.3 rather quickly. That, coupled with the fact that the focusing motor isn't up to Canon standards, it can be quite slow to focus; especially at the long end where the max aperture is 6.3. The Tamron is one of those lenses that looks good on paper...

Your going to be hard pressed replicating the "super zoom" of sorts on ff unless you either don't really care about IQ (the tamron you mentioned) or are willing to carry around a cinder block (canon 28-300L). I'd say get the 24-105 in the kit, it's a steal. If you need longer the 6d files can take a heavy crop, if you don't like the cropping results then look at a 70-200 f4 IS, 70-300 L, or 100-400 L. While you're at it pick up a 50 1.8 simply because it soooo darn cheap you may as well have one.

Your going to be hard pressed replicating the "super zoom" of sorts on ff unless you either don't really care about IQ (the tamron you mentioned) or are willing to carry around a cinder block (canon 28-300L).

Get the 24-105L over the Tamron 28-300.

A superzoom lens seems convenient, but there are always compromises. Usually, those compromises are optical - superzooms are generally not very sharp, have a lot of distortion and a lot of other optical issues. The 28-300L is a unique case, optically it's quite good (equivalent to the 24-105L, but covers a much broader range)...the compromises there are that it's a big, heavy, and expensive lens. I have one, use it as a travel lens (usually supplemented with a fast prime like the 35L or 135L), but I use the 24-105L a lot more.

Are you considering these lenses as a good all-purpose carry-around-all-day-so-you-don't-have-to-change-lenses lens, or as your only lens, period? Either way, I would be inclined to suggest you buy the 6D with the 24-105L as part of a kit, since that way the lens becomes quite a bargain (or, if you end up not wanting it, sell it and then the camera becomes a bargain). If it is to be your only lens, it would be a shame to move up to a FF camera and attach an inferior lens to it (though it may still make better pictures than it would on a crop sensor camera, and you would get far better results in low light). It would also be a shame to move up to a FF camera and not view the results on a big monitor or as fairly large prints, in which case you will see the difference (if you're not going to view your photos in such a way, why bother moving up to FF?).

I understand the appeal of such lenses, and they're one reason why I was interested in a Nikon D600 - Nikon has a 28-300 lens whose size and price are more manageable than Canon's, and it is by repute better than the Tamron. I rented a D600 + 28-300 and compared the results with photos taken with 6D + 70-300L. If you don't look very closely, the photos (on a 30" monitor) look much the same (I suspect that wouldn't be true with the Tamron, but I'm just guessing). Look more closely and it's quite obvious that the 70-300L is better; if the Nikon lens had been cheaper and if I had liked the D600 more I might have bought them anyway, but it isn't and I didn't. Is the convenience/quality trade-off worth it? Beats me. Why not buy the 6D + 24-105 kit, then rent the Tamron and see what you think? If you can't see a difference that matters to you, sell the 24-105 and buy the Tamron. If you can, try the 70-300 L....

Do my first "event" outdoors this weekend with FF and only used the 17-40 (most of the time) and the 24-105 for a few shots. These were people pictures in good outdoor light. I am pleased with the results even though I cropped a few to get the FOV I desired.

I will add this. Consider the Nikon system if you really want a great full frame superzoom that is affordable and compact. The Nikon D600 with a Nikon 28-300 would probably be ideal for you.

Canon's 28-300 superzoom, is a ridiculous design, in my opinion...as it is the size and weight of a pro lens, but is intended for people who aren't necessarily doing pro work. I'm sure some pro will pipe in and say they use it all the time, but that's not really what the lens is designed for. It's really a compromise design, and in my opinion, they should have done a 28-200 instead...to keep the size and weight down.

Also, consider renting whatever else you might be interested in. That way, you can make more informed decisions before purchase.

If you look at the below review of the Nikon 28-300, and compare it side by side in their test with say, the Nikon 24-70 f/2.8, you will find the 28-300 is actually sharper at the same aperture in much of that range (at least with the samples used for this test).

Thank you for your replies. In this case it really sounds for the Canon, as expected Regarding my other Canon gear, see post number 5 in this thread.It should be my "as a good all-purpose carry-around-all-day-so-you-don't-have-to-change-lenses lens" which would be most of the time mounted, at least not while I'm trying to picture wildlife (birds and such) or portraits. And yeah, for the reasons why I want to switch, read again the initial post. I mean I wouldn't mind getting a crop camera if it would provide the same ISO possibilities and viewfinder size, but that simply doesn't exist from Canon at the moment.Luckily I'm in no hurry of buying a new camera (first some holiday in the Philippines and Thailand next month), so I might experience the release of the successor of the 7D or 700D before I make my buy decision.But to summarize my thoughts about the new gear, I want a possible higher ISO for low light images the most